Substances necessary for obtaining a photographic image or compounds for obtaining a photographic image of higher quality are called photographically useful compounds. The photographic process, in its most basic form, is comprised of silver halide (capable of detecting light and storing it as latent image) and developer molecules (capable of converting the latent image to a visible image). These two chemistries, however, are incompatible, as unexposed silver halide is thermodynamically unstable with respect to reduction in the presence of developer molecules. Silver halide may also be unstable with respect to other additional photographically useful compound chemistries, which we will refer to using the term ‘active chemistry’. Examples of other potentially active chemistries in addition to developing agents include auxiliary developing agents, development accelerators, dyes, fogging agents, silver halide solvents, couplers, compounds which accelerate coupling reaction of couplers, bleaching accelerators, fixing accelerators and development inhibitors. The consequence of this is that many photographic components must be kept separate, each function performed in sequence and thus, modern photography requires multiple steps: exposure and processing.
Incorporation of active chemistry directly into film formulations, to either simplify or improve processing after exposure, has long been a goal in the photographic industry. Some photographically useful compounds are difficult to incorporate in a stable fashion into a light-sensitive material, however, or cause serious deterioration in the photographic capability if incorporated. These compounds, if incorporated directly into the photographic elements, typically need to be stabilized or rendered harmless by chemical modification prior to photographic processing. Methods of incorporating development and other active chemistries into photographic element formulations have been described in a number of patents and publications. Schleigh and Faul, in Research Disclosure 129 (1975) describe methods of appending color developers with “blocking” chemistry to prevent premature reaction. U. S. Pat. No. 6,261,757 to Irving et al. describes photographic articles in which developers and other photographic chemistries are ionically bound to the surface of ion-exchange resins. However, in such prior art methods imaging elements obtained are still frequently subject to poor keeping characteristics. It would be desirable to provide alternative methods for obtaining an imaging element with active chemistry photographically useful compounds directly incorporated therein, which exhibits good photographic photographic performance as well as excellent keeping characteristics.